Heater



FIG. 1 is a photograph illustrating a perspective view, taken from the front, top, and right side of a heater illustrating my new design;

FIG. 2 is a photograph illustrating a front elevation view thereof;

FIG. 3 is a photograph illustrating a right side elevation view thereof;

FIG. 4 is a photograph illustrating a left side elevation view thereof;

FIG. 5 is a photograph illustrating a rear elevation view thereof;

FIG. 6 is a photograph illustrating a top plan view thereof; and,

FIG. 7 is a photograph illustrating a bottom plan view thereof. 

The ornamental design for a heater, as shown and described. 